<template>
  <div id='home' class='wrapper'>
    <nav-bar class='home-nav'>
      <div slot='center'>购物街</div>
    </nav-bar>

    <tab-control :titles="['流行', '新款', '精选']" @tabClick='tabClick' ref='tabControl1' class="tab-control" v-show='isTabFixed'/>

    <scroll class='content'
            ref='scroll'
            :probe-type='3'
            @scroll='contentScroll'
            :pull-up-load='true'
            @pullingUp='loadMore'>
      <home-swiper :banners='banners' @swiperImageLoad='swiperImageLoad'/>
      <recommend-view :recommends='recommends'/>
      <feature-view/>
      <tab-control :titles="['流行', '新款', '精选']" @tabClick='tabClick' ref='tabControl2'/>
      <good-list :goods="showGoods"/>
    </scroll>
    <!-- native监听组件 -->
    <back-top @click.native='backClick' v-show='isShowBackTop'/>

  </div>
</template>

<script>
import HomeSwiper from './childComps/HomeSwiper'
import RecommendView from './childComps/RecommendView'
import FeatureView from './childComps/FeatureView'

import NavBar from 'components/common/navbar/NavBar'
import TabControl from 'components/common/tabControl/TabControl'
import GoodList from 'components/content/goods/GoodsList'
import Scroll from 'components/common/scroll/Scroll'
import BackTop from 'components/content/backTop/BackTop'

import {getHomeMultidata, getHomeGoods} from 'network/home'
import {debounce} from 'common/utils'

export default {
  name: 'Home',
  components: {
    NavBar,
    HomeSwiper,
    RecommendView,
    FeatureView,
    TabControl,
    GoodList,
    Scroll,
    BackTop,
    debounce
  },
  data() {
    return {
      banners: [],
      recommends: [],
      goods: {
        'pop': {page: 0, list: []},
        'new': {page: 0, list: []},
        'sell': {page: 0, list: []},
      },
      currentType: 'pop',
      isShowBackTop: false,
      isTabFixed: false,
      tabOffsetTop: 0,
      saveY: 0,
      itemImageListener: null
    }
  },
  computed: {
    showGoods() {
      return this.goods[this.currentType].list
    }
  },
  destroyed() {
    console.log('home destroyed')
  },
  activated() {
    this.$refs.scroll.scrollTo(0, this.saveY, 0)
    this.$refs.scroll.refresh()
  },
  deactivated() {
    //1. 保存Y值
    this.saveY = this.$refs.scroll.getScrollY()

    //2. 取消全局事件的监听
    this.$bus.$off('itemImageLoad', this.itemImageListener)
  },
  created() {
    //1.请求多个数据
    this.getHomeMultidata()

    //2.请求商品数据
    this.getHomeGoods('pop')
    this.getHomeGoods('new')
    this.getHomeGoods('sell')
  },
  mounted() {
    //1.图片加载完成的事件监听
    const refresh = debounce(this.$refs.scroll.refresh, 500)

    //2.对监听的事件进行保存
    this.itemImageListener = () => {
      refresh();
    }
    this.$bus.$on('itemImageLoad', this.itemImageListener)
  },
  methods: {
    backClick() {
      this.$refs.scroll.scrollTo(0, 0)
    },
    contentScroll(position) {
      //1.判断BackTop是否显示
      this.isShowBackTop = (-position.y) > 1000

      //2.决定tabControl是否吸顶(position: fixed)
      this.isTabFixed = (-position.y) > this.tabOffsetTop
    },
    loadMore() {
      this.getHomeGoods(this.currentType)
    },
    swiperImageLoad() {
      //2.获取tabControl的offsetTop
      //所有的组件都有一个属性$el, 用于获取组件中的元素
      this.tabOffsetTop = this.$refs.tabControl2.$el.offsetTop
    },
    /*
      事件监听相关的方法
    */
    tabClick(index) {
      switch (index) {
        case 0:
          this.currentType = 'pop'
          break;
        case 1:
          this.currentType = 'new'
          break;
        case 2:
          this.currentType = 'sell'
          break;
      }

      //让两个TabControl的currentIndex保持一致
      this.$refs.tabControl1.currentIndex = index;
      this.$refs.tabControl2.currentIndex = index;
    },
    /*
      网络请求相关的方法
    */
    getHomeMultidata() {
      getHomeMultidata().then(res => {
        this.banners = res.data.banner.list;
        this.recommends = res.data.recommend.list;
      })
    },
    getHomeGoods(type) {
      const page = this.goods[type].page + 1
      getHomeGoods(type, page).then(res => {
        this.goods[type].list.push(...res.data.list)
        this.goods[type].page += 1

        //完成了加载更多
        this.$refs.scroll.finishPullUp()
      })
    }
  }
}
</script>
<style scoped>
  #home {
    /*padding-top: 44px;*/
    height: 100vh;
    position: relative;
  }
  .home-nav {
    background-color: var(--color-tint);
    color: white;

    /* 在使用浏览器原生滚动时, 为了让导航不跟随一起滚动 */
    /*position: fixed;
    left: 0;
    right: 0;
    top: 0;
    z-index: 9;*/
  }
  .content {
    overflow: hidden;

    position: absolute;
    top: 44px;
    bottom: 49px;
    left: 0;
    right: 0;
  }
  .tab-control {
    position: relative;
    z-index: 9;
  }
  /*.content {
    height: calc(100% - 93px);
    overflow: hidden;
    margin-top: 44px;
  }*/
</style>
